curl -X POST https://api.open.cx/connect/threads/order_84421/messages \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "participant_id": "mrc_204",
    "lane": "customer_merchant",
    "text": "Out of garlic sauce — swap for tahini or refund the item?"
  }'

{
  "message": {
    "id": "msg_4t1a",
    "lane": "customer_merchant",
    "sender": { "participant_id": "prt_m32", "role": "merchant" },
    "text": "Out of garlic sauce — swap for tahini or refund the item?",
    "translations": {
      "ar": "نفدت صلصة الثوم — نستبدلها بالطحينة أم نسترد قيمة الصنف؟"
    },
    "created_at": "2026-07-30T14:12:40Z"
  }
}